For example,
'''[[File:Image.jpg|thumb]]'''
outputs,
<b data-parsoid='{"dsr":[0,30,3,3]}'><figure class="mw-default-size" typeof="mw:Image/Thumb" data-parsoid='{"optList":[{"ck":"thumbnail","ak":"thumb"}],"dsr":[3,27,2,2]}'><a href="./File:Image.jpg" data-parsoid='{"a":{"href":"./File:Image.jpg"},"sa":{"href":"File:Image.jpg"},"dsr":[5,25,null,null]}'><img resource="./File:Image.jpg" src="//upload.wikimedia.org/wikipedia/commons/thumb/7/78/Image.jpg/220px-Image.jpg" data-file-width="500" data-file-height="500" data-file-type="bitmap" height="220" width="220" data-parsoid='{"a":{"resource":"./File:Image.jpg","height":"220","width":"220"},"sa":{"resource":"File:Image.jpg"}}'/></a></figure></b>and,
<small> * hi * ho </small>
outputs,
<p data-parsoid='{"dsr":[0,7,0,0]}'><small data-parsoid='{"stx":"html","autoInsertedEnd":true,"dsr":[0,7,7,0]}'></small></p><small data-parsoid='{"stx":"html","autoInsertedEnd":true,"autoInsertedStart":true,"dsr":[7,17,0,0]}'>
<ul data-parsoid='{"dsr":[8,17,0,0]}'><li data-parsoid='{"dsr":[8,12,1,0]}'>hi</li>
<li data-parsoid='{"dsr":[13,17,1,0]}'>ho</li></ul></small>
<p data-parsoid='{"dsr":[18,26,0,0]}'><small data-parsoid='{"stx":"html","autoInsertedStart":true,"dsr":[18,26,0,8]}'></small></p>While these both render identically to the PHP parser / Remex combo, they are uneditable in VisualEditor.
From the commit message of https://github.com/wikimedia/parsoid/commit/d473791ea982178af7a0fe15aff5cf8e21aaa5e8
However, in T68749, there's a request/argument to avoid nesting blocks
in formatting tags, since VE can't handle that data model violation and
marks the nodes as uneditable. In the past, we've supported that
inconsistently. For example, the case in "1. List embedded in a
formatting tag" is uneditable, despite it being a popular pattern.
In "2. Treebuilder fixup of formatting elt", only one of two images was
editable.We should consider reopening T68749 and adding a pass to solve the issue
generally. Note that the Parsoid output now matches Remex so any
changes to the DOM is explicitly introducing a difference to support
editing clients, and should be noted as such.